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Trying to get a handle on growing

For the last two years, I have been trying to learn everything I possibly can about growing plants indoors (in bedrooms or a green house) from October-June. Have almost worn out my "G," "O," "L" and "E" keys, bought books, read hundreds of papers. Following is some things I have learned:

Besides growing media and nutrients, the other two major factors that influence fruit production of tomatoes (and likely their relatives: peppers and eggplants) are GDD (Growing Degree Days) and DLI (Daily Light Integral). You can call it 3DLIG!

Phenolgy refers to plants' response to climate, mostly heat. GDD measures the amount of days that contribute to plants growing and ripening fruit. For instance, it takes 1400-1900 GDD for tomatoes to ripen, based on what type of plant it is (early, mid-season, late; determinate or indeterminate; size of fruit, etc.) DLI is a measure of accumulated light in the PAR range the plant receives in a day. Tomatoes and peppers will "grow" under 10-14 moles (that the measurement used) minimally. To be productive, they need 20-22 moles per day.

Of course, there are limits - if the temps are above 95 or so, blooms have a hard time developing and fruit setting, so calculations of GDD needs to be capped at 95. More than 30 moles per day will not hasten plant development, so that needs to be taken into account.

The bottom line, not including growing media and nutrients, I think an ideal model of lighting and heat for growing indoors should be able to be formulated.

If you have read this far, this is, from an expression from my younger days, where the rubber meets the road.

The idea is to combine the amount of light and heat needed per day to get ripe fruit in the smallest amount of time. I'll use a 400-watt MH light as my example. It provides 36,000 lumens, so to produce 20 moles per day I need to run it 12 hours per day - anything over that is wasted. I want to start harvesting ripe tomatoes 80 days after being transplanted, they are determinate, medium-size fruit that require 1800 GDD to produce ripe fruit. 1800 divided by 80 tells me I need about 22 GD per day if I want to harvest fruit in my time frame. So I need to maintain at least a 77 degree temp (based on toms liking 55 degrees as the minimum temp) or at least average it.

OK, I'll leave now and go talk to my plants! :crazy: Just stuff I found interesting!

Mike
 
Great stuff! It would do my head in working that all out but it's so nice when other people do the work! :D
 
Nice one Mike; I tend toward your end of things even though I'm an outside grower. It's info like that which helps me to deal with the heat issues here and act accordingly. My plants are all going under shade cloth; potted and in the ground both. Cheers.
 
I haven't put it into those words but agree with what your research shows...great research Mike
 
I only use the energy of the sun to grow my peppers so I'm kind of stuck with what the weather brings my way...
Anyway it was good reading and I hope you achieve your goal to minimize fruit rippening time.

Keep us posted on your progress. :)
 
Yeah, the info is more pertinent to indoor growing or growing under artificial lights than for those plants in a garden. I knew about the lighting requirements but it was the Growing Degree Days that intrigued me. Up to a point, the warmer I can keep the GH or upstairs grow room, the quicker I will get ripe fruit.

In the dead of winter, the room up there doesn't get below 50 degrees and on a sunny afternoon, even with single-digit outside temps, it can get up to 75 or higher.

Since tomatoes are day-neutral, the lighting cycle does not matter. I can run lights (1800 watts of them) from midnight until noon and they will get just as many moles as from 8-8. But, because the room gets cooler at night, I would be adding heat without any additional costs. While the room would not be as warm during the afternoon, it would still be a net addition as many researchers cap temps at 85-90 when calculating GDD, as the extra heat does not make a difference. Adding an average of three degrees per day over the first two months, while the plant is growing and starting to set blooms, would add 180 GDD or 10 percent of the total needed.

Another advantage I see would be a shorter time for fruit to ripen. Last winter, I could get the tomatoes to grow, bloom, set fruit, and it would develop - to a point. But despite plenty of light, it took way longer than normal for the tomatoes to ripen, and several of them developed BER or other problems. It may not have been related to the amount of heat, but the soil was watered evenly, I used Tomato-tone fertilizer which is designed especially for maters and I did not have any infestations.

I'm almost looking forward to winter to see how this works!

Mike
 
I credit you for giving me the idea to put dirt in my soil mix. I know it's kind of a no-brainer, but I just started doing it this year and it works great and saves me using so much expensive stuff.
Thanks
 
ABM,

Not a problem - I found out the hard way. My plants started out great, grew fast, started blooming and then went no where!

I'm working on a new batch for my fall plants. This time, I'll add a bit more compost and some aged horse manure. Hopefully, I'll have about 34 plants for my GH, though I will let them grow outside until the frost gets here - too hot inside it!

Mike
 
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